1. Field of the Invention
The present invention relates to a method of manufacturing thin-film solar cells.
2. Description of the Related Art
CuInSe.sub.2 (copper indium selenide)--thin-film solar cells are normally produced by depositing a molybdenum (Mo) back contact onto a substrate, for instance a glass substrate. Copper, indium and selenide are then deposited onto the back contact to form a CuInSe.sub.2 layer, the CuInSe.sub.2 being formed by chemical reaction in a selenium-containing atmosphere. In this stage of manufacture, the structure is subjected to a temperature in the range of 350-600.degree. C.
The CuInSe.sub.2 layer is a p-type semiconductor. An n-type semiconductor is deposited on the CuInSe.sub.2 layer to form a pn-junction, which forms the actual solar cell. The n-type semiconductor is most often comprised of a thin layer of CdS and a much thicker layer of ZnO, which provides the best structure. The ZnO layer forms a front side contact at the same time.
It is desired to increase the efficiency of solar cells of this kind.
The present invention provides a method of manufacturing solar cells which greatly increases the efficiency of the solar cell produced.